I am building a website (probably in Wordpress) which takes data from a number of different sources for display on various pages.
The sources:
A Twitter feed
A Flickr feed
A database on a remote server
A local database
From each source I will mainly retrieve
A short string, e.g. for Twitter, the Tweet, and from the local database the title of a blog page.
An associated image, if one exists
A link identifying the content at its source
My question is:
What is the best way to a) store the data and b) retrieve the data
My thinking is:
i) Write a script that is run every 2 or so minutes on a cron job
ii) the script retrieves data from all sources and stores it in the local database
iii) application code can then retrieve all data from the one source, the local database
This should make application code easier to manage - we only ever draw data from one source in application code - and that's the main appeal. But is it overkill for a relatively small site?
I would recommend putting the twitter feed and flickr feed in JavaScript. Both flickr and twitter have REST APIs. By putting it on the client you free up resources on your server, create less complexity, your users won't be waiting around for your server to fetch the data, and you can let twitter and flickr cache the data for you.
This assumes you know JavaScript. Once you get past JavaScript quirks, it's not a bad language. Give Jquery a try. JQuery Twitter plugin Flickery JQuery plugin. There are others, that's just the first results from Google.
As for your data on the local server and remote server, that will depend more on the data that is being fetched. I would go with whatever you can develop the fastest and gives acceptable results. If that means making a REST call from server to sever, then go for it. IF the remote server is slow to respond, I would go the AJAX REST API method.
And for the local database, you are going to have to write server side code for that, so I would do that inside the Wordpress "framework".
Hope that helps.
Related
I am building a web app using nodeJS with an angular based frontend and a Firebase/AngularFire2 backend. I have a list of about 80 cities and couple of details about each of them that I need to display with checkboxes for the user.
Should I save them as a json object in a .json file on the server and call it, or just store it in my Real-time Database and query it? Are there any speed/memory benefits to either?
There are two scenarios :
1.Your task is search oriented. You have to query the data and manipulate it. Memory management is key issues for you. You want some complex searching methods on your data. Then go for the database.
2.Your task require whole data at a time. You don't need to worry about memory management. Then directly load the data from file. Obviously this method will save the connection making time with your database. It will work as simple as file streams. [suggested for your case]
Please presume that I do not know anything about any of the things I will be mentioning because I really do not.
Most OpenData sites have the possibility of exporting the presented file either in for example .csv or .json formats (Example). They also always have an API tab (Example API).
I presume using the API would mean that if the data is updated you would receive the change whereas exporting it as .csv would mean the content will not be changed anymore.
My questions is: how does one use this API code to display the same table one would get when exporting a .csv file.
Would you use a database to extract this information? What kind of database and how do you link the API to the database?
I presume using the API would mean that if the data is updated you
would receive the change whereas exporting it as .csv would mean the
content will not be changed anymore.
You are correct in the sense that, if you download the csv to your computer, that csv file won't be updated any more.
An API is something you would call - in this case, you can call the API, saying "Hey, do you have the latest data on xxx?", and you will be given back the latest information about what you have asked. This does not mean though, that this site will notify you when there's a new update - you will have to keep calling the API (every hour, every day etc) to see if there are any changes.
My questions is: how does one use this API code to display the same
table one would get when exporting a .csv file.
You would:
Call the API from a server code, or a cloud service
Let the server code or cloud service decipher (or "Parse") the response
Use the deciphered response to create a table made out of HTML, or to place it into a database
Would you use a database to extract this information? What kind of
database and how do you link the API to the database?
You wouldn't necessarily need a database to extract information, although a database would be nice to place the final data inside.
You would first need some sort of way to "call the REST API". There are many ways to do this - using Shell Script, using Python, using Excel VBA etc.
I understand this is hard to visualize, so here is an example of step 1, where you can retrieve information.
Try placing in the below URL (taken from the site you showed us) in your address bar of your Chrome browser, and hit enter
http://opendata.brussels.be/api/records/1.0/search/?dataset=associations-clubs-sportifs
See how it gives back a lot of text with many brackets and commas? You've basically asked the site to give you some data, and this is the response they gave back (different browsers work differently - IE asks you to download the response as a .json file). You've basically called an API.
To see this data more cleanly, open your developer tools of your Chrome browser, and enter the following JavaScript code
var url = 'http://opendata.brussels.be/api/records/1.0/search/?dataset=associations-clubs-sportifs';
var xhr = new XMLHttpRequest();
xhr.open('GET', url);
xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');
xhr.onload = function() {
if (xhr.status === 200) {
// success
console.log(JSON.parse(xhr.responseText));
} else {
// error
console.log(JSON.parse(xhr.responseText));
}
};
xhr.send();
When you hit enter, a response will come back, stating "Object". If you click through the arrows, you can see this is a cleaner version of the data we just saw - more human readable.
In this case, I used JavaScript to retrieve the data, but you can use whatever code you want. You could proceed to use JavaScript to decipher the data, manipulate it, and push it into a database.
kintone is an online cloud database where you can customize it to run JavaScript codes, and have it store the data in their database, so you'll have the data stored online like in the below image. This is just one example of a database you can use.
There are other cloud services which allow you to connect API end points of different services with each other, like IFTTT and Zapier, but I'm not sure if they connect with open data.
The page you linked to shows that the API returns values as a JSON object. To access the data you can just send an appropriate http request and the response will be the requested data as a JSON. You can send requests like that over your browser if you want to.
Most languages allow JSON objects to be manipulated pro grammatically if you need to do work on the data.
Restful APIs publish model is "request and publish". Wen you request data via an API endpoint, you would receive response strings in JSON objects, CSV tables or XML.
The publisher, in this case Opendata.brussel.be would update their database on regular basis and publish the results via an API endpoint.
If you want to download the table as a relational data table in a CSV file, you'd need to parse the JSON objects into relational tables. This can be tricky since each JSON response string can vary in their paths.
There're several ways to do it. You can either write scripts to flatten the JSON objects or use a tool to parse and flatten the objects for you.
I use a tool called Acho to turn API endpoints into CSV files. It would parse almost all API endpoints through the parameters and even configure for multiple requests, such as iterative and recursive requests.
Acho API parser
My question is about how to store data which once was received online and still can be processed after the mobile device got offline and/or was restarted.
I'm using AngularJS with Ionic (PhoneGap) for building apps. But my question is not explicitly adressing these technologies.
Best practices, patterns or algorythms would be very helpful to me or even some useful articles or key words.
1) The most simple challenge is to make my app more user-friendly by making its functionality usable not only if the device is online but also in offline mode. In my case this implies that I have to make the last fetched online data available for later use (while device is offline and also after restarting the device!).
2) A bit more difficult is to reduce the communication costs by only synchronizing the server side changed data when the device reconnects to the internet.
3) Entities can also be produced on client side while the device is offline and they must get synchronized to the server too. There are no potential risks of conflicts because the users don't share Entities with write access.
4) I use Googles and Apples push services to inform the devices about newer entity versions, which should get updated on client side. So polling isn't needed.
Client side technologies: Javascript, AngularJS Framework, Ionic Framework, SQLite (WebSQL) or IndexedDB, PhoneGap (Cordova)
Server side technologies: Java EE, JPA, MySQL
Data Format and communication: JSON over REST / http, Googles and Apples push services for server-to-client messaging
1) Store the needed data inside a local SQLite database, and pull it out when the app starts/resumes.
2)In the MySQL database you need a table that creates new entries when you update/change/create content. You would need to store an id and a timestamp (maybe a boolean value if the content was deleted).
On the device you would make a request to the server to send the data from that table and compare it with the locally stored data. If there is a new id or the timestamp has change make a new request to pull the updated data.
3)Store the created data locally with a flag that it isn't synced with the server. When the device then goes online again check for not synced flags and send the data to the server with an identifier to know which device it comes from and where to save it.
4)See 2)
You could make a Java script which checks every x minutes for updated entries and send an automatic push Notification with it. What you would need is 2 tables, one with the newest updates and one with the updates that got pulled by the device(just id's and timestamps, not all the data).
I hope this was helpful, if something new comes to my mind I will update this answer.
I'm currently developing a mobile application that will fetch data from server by request (page load) or by notification received (e.g. GCM).
Currently I'm starting to think about how to build the backend for that app.
I thought about using PHP to handle the http requests to my database (mySQL) and to return the response as JSON. As I see it there are many ways to implement such server and would like to hear to hear thoughts about my ideas for implementations:
1. create a single php page that will receive an Enum/Query, execute and send the results.
2. create a php page for every query needs to be made.
Which of my implementations should I use? if none please suggest another. Thank you.
P.S, this server will only use as a fetcher for SQL and push notifications. if you have any suggestion past experience about how to perform it (framework, language, anything that comes to mind) I'd be happy to learn.
You can use PHP REST Data services framework https://github.com/chaturadilan/PHP-Data-Services
I am also looking for information about how to power a web and mobile application that has to get and save data on the server.
I've been working with a PHP framework such as Yii Framework, and I know that this framework, and others, have the possibility to create a API/Web service.
APIS can be SOAP or REST, you should read about the differences of both to see wich is best for mobile. I think the main and most important one is that for SOAP, you need a Soap Client library on the device you are trying to connect, but for REST you just make a http request to the url.
I have built a SOAP API with Yii, is quite easy, and I have use it to communicate between two websites, to get and put data in the same database.
As for your question regarding to use one file or multiple files for every request, in the case of SOAP built on Yii, you have to normally define all the functions available to the API on the server side in only one file(controller) and to connect to that webservice you end up doing:
$client=new SoapClient("url/of/webservice);
$result=$client->methodName($param1, $param2, etc..);
So basically what you get is that from your client, you can run any method defined on the server side with the parameters that you wish.
Assuming that you use to work program php in the "classic way" I suggest you should start learning a framework, there are many reasons to do it but in the end, it is because the code will result more clean and stable, for example:
You shouldn't be writing manual queries (sometimes yes), but you can use the framework's models to handle data validation and storage into the database.
Here are some links:
http://www.larryullman.com/series/learning-the-yii-framework/
http://www.yiiframework.com/doc/guide/1.1/en/topics.webservice
http://www.yiiframework.com/wiki/175/how-to-create-a-rest-api/
As I said, I am also looking to learn how to better power a mobile application, I know this can be achieved with a API, but I don't know if that is the only way.
create a single php page that will receive an Enum/Query, execute and send the results.
I created a single PHP file named api.php that does exactly this, the project is named PHP-CRUD-API. It is quite popular.
It should take care of the boring part of the job and provides a sort of a framework to get started.
Talking about frameworks: you can integrate the script in Laravel, Symfony or SlimPHP to name a few.
I am using Azure Mobile Services to store images for a web application.
I have managed to successfully upload images to a private container. I've followed the logic in this introductory guide (http://code.msdn.microsoft.com/windowsapps/Upload-File-to-Windows-c9169190), i.e. when uploading the file to the database an SAS is generated by a node script called when inserting a record into a table.
One of the reasons to use this approach from mobile apps is so that the storage key is not stored within the application source itself.
Conforming with that idea I am now struggling to find an example of how to download the images.
Perhaps I should update the read function for the same table and have that return an SAS which can be used to accessed the image.
Does this sound reasonable or are they better approaches?
Any assistance is greatly appreciated.
It sounds to me like you are on the right track. If you are storing the image in a private container and want the mobile device to read it back then yes, you will want to produce a SAS that allows reading and get that back to the device. The device code can then make a call directly against BLOB storage using that SAS URL to retrieve the image.
This applies only if you want the container private. If the container is public then just returning the URL (like they have in the article you link to) should be fine.
It also depends on how private you care the image to be. For example, let's say you have a container created per user. If the container has a Shared Access Signature Policy on it with a really far off expiration date then technically someone still needs the URL with the SAS to view it, but you can create that SAS and store it like the sample. The mobile app can then be given the URL when it reads data from your service and get to the BLOB directly without having it create an additional SAS. In my opinion this option only really works if the images aren't going to be around very long, or you don't really care that if someone sniffs the URL from the network traffic that they can access it.
If you want it fairly secure and do not know how long the images will be around, then you should go with your stated approach of getting a SAS for read when the app reads from the related table data. The SAS can have a fairly short expiry on it and the mobile device can cache the result.